hi i have a question i have a 04 2.0 dti vectra estate the engine gets noisy when going over 2500 revs. any got a clue why getting no fault codes. thought it might be sticking waist gate but surly that would give me a bost pressure fault code. car runs fine turbo and everything. cleaned egr, inlet manifold, changed maf, thermostat(car was not heating up and had bad fuel consumption). any help would be well appreciated as im banging my head against a wall.......